#include "dna.h"
#include <vector>
using namespace std;
int n, pre[100100][3][3];
int tran(char c) {
if(c == 'A') return 0;
if(c == 'T') return 1;
return 2;
}
void init(std::string a, std::string b) {
n = a.size();
for(int i = 0; i < n; i++) {
int x = tran(a[i]), y = tran(b[i]);
for(int j = 0; j < 3; j++) {
for(int k = 0; k < 3; k++) {
pre[i + 1][j][k] = pre[i][j][k] + (j == x && k == y);
}
}
}
}
int get_distance(int x, int y) {
x++, y++;
vector<int> acnt(3), bcnt(3);
vector<vector<int>> m(3, vector<int>(3));
for(int i = 0; i < 3; i++) {
for(int j = 0; j < 3; j++) {
acnt[i] += pre[y][i][j] - pre[x - 1][i][j];
bcnt[j] += pre[y][i][j] - pre[x - 1][i][j];
m[i][j] = pre[y][i][j] - pre[x - 1][i][j];
}
}
for(int i = 0; i < 3; i++)
if(acnt[i] != bcnt[i])
return -1;
int ans = 0;
for(int i = 0; i < 3; i++) {
for(int j = i + 1; j < 3; j++) {
int now = min(m[i][j], m[j][i]);
m[i][j] -= now;
m[j][i] -= now;
ans += now;
}
}
if(m[0][1]) {
if(m[0][1] != m[1][2] || m[0][1] != m[2][0])
while(1);
if(m[0][2] || m[1][0] || m[2][1])
while(1);
ans += m[0][1] * 2;
} else if(m[0][2]) {
if(m[0][2] != m[1][0] || m[0][2] != m[2][1])
while(1);
if(m[0][1] || m[1][2] || m[2][0])
while(1);
ans += m[0][2] * 2;
}
return ans;
}
